LEDs are of interest for fibre optics because of five inherent characteristics..
How it works?
Spectrum of an LED
Modulation of LED
LED Vs. Laser diode
disadvantages of LED
The attached narrated power point presentation attempts to explain the methods of computation of total power loss and system rise time in a fiber optic link. The material will be useful for KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
This narrated power point presentation attempts to explain the various dispersion mechanisms that are observed in optical fibers. Some fundamental terms and concepts are also discussed. The material will be useful for KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
The following ppt gives overview about Optical Communication and the underlying principle with the general overview of all the contents for optical communication
LEDs are of interest for fibre optics because of five inherent characteristics..
How it works?
Spectrum of an LED
Modulation of LED
LED Vs. Laser diode
disadvantages of LED
The attached narrated power point presentation attempts to explain the methods of computation of total power loss and system rise time in a fiber optic link. The material will be useful for KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
This narrated power point presentation attempts to explain the various dispersion mechanisms that are observed in optical fibers. Some fundamental terms and concepts are also discussed. The material will be useful for KTU final year B Tech students who prepare for the subject EC 405, Optical Communications.
The following ppt gives overview about Optical Communication and the underlying principle with the general overview of all the contents for optical communication
A Klystron is a vacuum tube that can be used either as a generator or as an amplifier or as an oscillator, at microwave frequencies.The Klystron is a linear beam device; that is, the electron flow is in a straight line focused by an axial magnetic field.
A Klystron is a vacuum tube that can be used either as a generator or as an amplifier or as an oscillator, at microwave frequencies.The Klystron is a linear beam device; that is, the electron flow is in a straight line focused by an axial magnetic field.
An optical fiber (or optical fibre) is a flexible, transparent fiber made of high quality extruded glass (silica) or plastic, slightly thicker than a human hair. It can function as a waveguide, or “light pipe”, to transmit light between the two ends of the fiber.
Fiber optics and how optical communication takes place.Details regarding how signalling,routing and switching occurs in optical network .A little detail about various equipments used in optical communication.
link of a reference: http://www.slideshare.net/zena_mohammed/advanced-digital-signal-processing-book. digital_signal_processing__a_practical_approach. this reference for asked me for pictures in presentation of Multirate Digital Signal Processing.
An optical fiber is a hair thin cylindrical fiber of glass or any transparent dielectric medium.
The fiber which are used for optical communication are wave guides made of transparent dielectrics.
Its function is to guide visible and infrared light over long distances.
Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. The light forms anelectromagnetic carrier wave that is modulated to carry information.
Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication, and cable television signals.
The process of communicating using fiber-optics involves the following basic steps: Creating the optical signal involving the use of a transmitter, relaying the signal along the fiber, ensuring that the signal does not become too distorted or weak, receiving the optical signal, and converting it into an electrical signal.
Optical cable: It serves as transmission medium.
Optical detector: It is responsible for optical to electrical conversion of data and hence responsible for demodulation of the optical carrier. It may be a photodiodes, phototransistor, and photoconductors.
Electrical receiver: It is used for electrical interfacing at the receiver end of the optical link and to perform the signal processing electrically.
Destination: It is the final point at which we receive the information in the form of electrical signal.
Applications -In telecommunication field
In space applications
Broadband applications
Computer applications industrial applications
Mining applications
In medical applications
In military applications etc.
Voice Transmission System Based on Laser Torchijtsrd
This paper is designed for voice transmission system based on laser torch. In this system, it has two parts transmitting section and receiving section. The transmitting section mainly comprises with condenser microphone, IC 741, BC 548, BD 139 and laser torch. The receiving section composes with L14f1 photo transistor, LM 386 and Loud speaker. If there is any obstruction in the path of the laser beam, no sound will be heard from the receiver. The gain of the op amp can be controlled with the help of 1 mega ohm pot meter variable resistor. The AF output from the amplifier is coupled to the base of transistor BD 139, which in turn, modulates the laser beam. The receiver circuit uses NPN photo transistor as the light sensor that is followed by two stage transistor preamplifier and LM 386 based audio power amplifier. The receiver does not need any complicated alignment. The photo transistor is kept towards the remote transmitter's laser point and the volume control is adjusted for a clear sound. Thet Thet Htun | Hla Yamin | May Zin Oo "Voice Transmission System Based on Laser Torch" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26790.pdfPaper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/26790/voice-transmission-system-based-on-laser-torch/thet-thet-htun
Circuits for Optical Based Line of Sight Voice CommunicationjournalBEEI
We present here line of sight communication between a person and his neighbour with the help of optical signal produced by a laser torch which act as a carrier. It is therefore a wireless communication and the transmission can go up to 500 meters. We used photodiode to receive the signal at the receiver. The transmitter circuit comprises condenser microphone transistor amplifier BC547 followed by an op-amp stage built around µA741. When we give a voice signal from the mike, it converts the voice signal into the electrical signal. This electrical signal is fed to IC741 (op-amp) for amplification. The gain of the op-amp can be controlled with the help of 1-mega-ohm potentiometer. The AF output from IC is coupled to the base of a class B amplifier which, in turn, modulates the signal. The transmitter uses 5V power supply. However, the 3-volt laser torch (after removal of its battery) can be directly connected to the circuit-with the body of the torch connected to the class B. The photodiode converts the optical signal into electrical signal and again this signal is amplified using IC741 and a combination of class B push pull amplifiers. The receiver circuit uses an NPN photodiode as the light sensor that is followed by a two-stage transistor preamplifier and IC741 based audio Power amplifier. The receiver does not need any complicated alignment. Just keep the photodiode oriented towards the remote transmitter’s laser point and adjust the volume control for a clear sound. The sensor must not directly face the sun.
Transmitting audio signal using ir led.
other than audio we can also use melody generator(um66), in place of audio signal.
or we can use microphone in place of audio input.
and instead of ir receiver we can make use of photo transistor.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
#vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore#blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #blackmagicforlove #blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #Amilbabainuk #amilbabainspain #amilbabaindubai #Amilbabainnorway #amilbabainkrachi #amilbabainlahore #amilbabaingujranwalan #amilbabainislamabad
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
3. Enormous potential bandwidth.
The optical carrier frequency in the range 1013
to 1016
Hz (generally in the
near infrared around 1014 Hz or 105 GHz) yields a far greater potential
transmission bandwidth than metallic cable systems.
Small size and weight.
Optical fibers have very small diameters which are often no greater than the
diameter of a human hair. Hence, even when such fibers are covered with
protective coatings they are far smaller and much lighter than corresponding
copper cables.
Signal security.
The light from optical fibers does not radiate significantly and
therefore they provide a high degree of signal security.
Advantages of Optical Fiber Communication
4. Electrical Isolation.
Optical fibers which are fabricated from glass, or sometimes a plastic
polymer, are electrical insulators and therefore, unlike their metallic
counterparts, they do not exhibit earth loop and interface problems.
Immunity to interference and crosstalk.
Optical fibers form a dielectric waveguide and are therefore free from
electromagnetic interference (EMI), radio-frequency interference
(RFI), or switching transients giving electromagnetic pulses (EMPs).
Low transmission loss.
Fibers have been fabricated with losses as low as 0.15 dB km−1
and
this feature has become a major advantage of optical fiber
communications
5. Ruggedness and flexibility
Although protective coatings are essential, optical fibers may be
manufactured with very high tensile strengths
Potential low cost.
The glass which generally provides the optical fiber transmission medium is made
from sand – not a scarce resource.
System reliability and ease of maintenance.
The reliability of the optical components is no longer a problem with predicted
lifetimes of 20 to 30 years being quite common. Both these factors also tend to
reduce maintenance time and costs.
6. Optical Transmitters (Optical System)
The role of the optical transmitter is to:
oconvert the electrical signal into optical form, and
olaunch the resulting optical signal into the optical
fiber.
Two Important Specifications of The Optical
Transmitter:
(i) the spectral linewidth and
(ii) the extinction ratio.
The values that can be achieved for these parameters
depends on whether direct or external modulation is
used.
7. Extinction Ratio.
▫ Optical transmitters, no matter if directly or externally modulated. do not shut off
completely when a zero is transmitted. This undesired effect is quantified by the
extinction ratio (ER), which is defined as follows:
ER=
𝑃1
𝑃0
where 𝑃0 is the optical power emitted for a zero and 𝑃1 the power for a one.
the spectral line-width
• In practice, it is difficult to build a transmitter with a linewidth as narrow
0.08nm for . only some types of external modulators can come
close to this ideal. Optical pulses that do have this narrow spectrum are
known as transform limited pulses.
Incoherent emission from an LED usually displays a spectral line-width of between
20 and 50 nm when operating in the 0.8 to 0.9 μm wavelength range.
LEDs have wide spectral line-width as compare to ILDs.
Wide line width of the LEDs causes material dispersion within the fiber.
8. The optical transmitter consists of the following
components:
Optical Source.
Electrical Pulse
Generator.
Optical Modulator .
9. Optical Light Sources
LED
oSemiconductor device
oMedium modulation
speed
oIncoherent output light
oMainly used for short
range FSO systems
(shorter than 1 km)
Laser
oHighly directional beam
profile
oUsed for long range
FSO systems
oHigh modulation
speed
oCoherent output light
Lamp
oLower efficiency
compared to LED and
laser
oLower cost
oLow modulation speed
oIncoherent output light
oProvides higher power
13. Optical transmitter is a device that generates the signal sent
through optical fibers.
The basic elements of optical fiber transmitter are shown in
Figure below :
Transmitter Design
14. The basic elements of optical fiber transmitter:
oElectronic Interface:
There is wires standard electronic connection or pins energizing the
transmitter. They provide power Electronic I/P and O/P Optical
signals.
oElectronic Processing
In some transmitters the I/P Electrical signals are electronically
processed to put them into of suitable from to drive the light source.
oDrive CKT
This depends on application, requirements, data format and the light
source.
15. oOptical Monitor
It Monitors the O/P of the LASER and provides feedback to
the drive CKT so that the O/P power remains stable.
oTemperature Monitor
The characteristic of semi-conductor LASER changes in
temperature. The lifetime of LASER decreases with increase
in operating temp and the O/P power also decrease which
produce some change in O/P wavelength of the light, to keep
the operating temp stable the Thermo-electric coolers are used
in optical fiber transmitters these coolers control the temp of
LASER.
16. Optical Modulator
The following modulators commonly are used in optical
transmitters:
o The electroabsorption modulator (EAM), which is small and
can be driven with a reasonably small voltage swing.
Electrically, it is a reverse-biased p-n junction.
o The Mach-Zehnder modulator (MZM), which generates the
highest-quality optical pulses with a controlled amount of
chirp and a high extinction ratio. Electrically, it is a
(terminated) transmission line.
• The maximum transmission distance that can be achieved
in an optical communication system is determined by a
combination of the chromatic dispersion limit, the
polarization-mode dispersion (PMD) limit, and the
attenuation limit.
Editor's Notes
(a) Enormous potential bandwidth.
The optical carrier frequency in the range 1013 to 1016 Hz (generally in the near infrared around 1014 Hz or 105 GHz) yields a far greater potential transmission bandwidth than metallic cable systems (i.e. coaxial cable bandwidth typically around 20 MHz over distances up to a maximum of 10 km) or even millimeter wave radio systems (i.e. systems currently operating with modulation bandwidths of 700 MHz over a few hundreds of meters).
(b) Small size and weight.
Optical fibers have very small diameters which are often no greater than the diameter of a human hair. Hence, even when such fibers are covered with protective coatings they are far smaller and much lighter than corresponding copper cables.
(f) Low transmission loss.
The development of optical fibers over the last 20 years has resulted in the production of optical fiber cables which exhibit very low attenuation or transmission loss in comparison with the best copper conductors. Fibers have been fabricated with losses as low as 0.15 dB km−1 and this feature has become a major advantage of optical fiber communications
(g) Ruggedness and flexibility.
cable structures have been developed which have proved flexible, compact and extremely rugged. Taking the size and weight advantage into account, these optical fiber cables are generally superior in terms of storage, transportation, handling and installation to corresponding copper cables, while exhibiting at least comparable strength and durability.
(c) Electrical isolation.
Optical fibers which are fabricated from glass, or sometimes a plastic polymer, are electrical insulators and therefore, unlike their metallic counterparts, they do not exhibit earth loop and interface problems.
(d) Immunity to interference and crosstalk.
Optical fibers form a dielectric waveguide and are therefore free from electromagnetic interference (EMI), radio-frequency interference (RFI), or switching transients giving electromagnetic pulses (EMPs). Hence the operation of an optical fiber communication system is unaffected by transmission through an electrically noisy environment and the fiber cable requires no shielding from EMI. The fiber cable is also not susceptible to lightning strikes if used overhead rather than underground.
(e) Signal security.
The light from optical fibers does not radiate significantly and therefore they provide a high degree of signal security.
(h) System reliability and ease of maintenance.
system reliability is generally enhanced in comparison with conventional electrical conductor systems. Furthermore, the reliability of the optical components is no longer a problem with predicted lifetimes of 20 to 30 years being quite common. Both these factors also tend to reduce maintenance time and costs.
(i) Potential low cost.
The glass which generally provides the optical fiber transmission medium is made from sand – not a scarce resource. So, in comparison with copper conductors, optical fibers offer the potential for low-cost line communication.